I do agree with the sentiment that "if all the winners at the AHA competi-
tion used liquid yeast, all that might prove is that all of the participants
used liquid yeast." However, here are some more *complete* statistics:

1990 Competition (1548 entries)

technique entered placed 1st, 2nd or 3rd

malt extract 22% 20%
extract + mash 27% 20%
all-grain 51% 60%

glass fermenter 85% 86%
plastic 10% 8%
stainless 5% 5%

2-stage fermentation 74% 77%
single stage 26% 23%

dry yeast 33% 16%
liquid yeast 67% 84%

(source: 1990 Special Issue, Zymurgy, vol. 13 no. 4, p. 61)

The conclusion upon first seeing these is that liquid yeast is the most
important thing you can do to improve your beer, more so than mashing,
lagering or fermenting in glass over plastic, although each of these
seems to be a "step up".

Now, the caveat here is that more experienced, better brewers tend to use
more advanced techniques, so that results attained may be the result of
the technique OR they may be the result of the beer having been brewed by
a more experienced, better brewer.

To me it doesn't matter, the fact that more experienced, better brewers
tend to use a technique is a strong recommendation to me that *I* should
use said technique. The conclusion is the same.

Besides, the jump from 67% to 84% in liquid yeast cited above is *tremendous*
evidence that this is a great way to improve your beer. But again, it is
only correlation, as statistical types will likely point out.

I don't have the numbers on me from 1991 although they were published.
I think the jump in liquid yeast was *not* as high, but that was partly
because the overall % of entries using liquid yeast jumped quite a bit.